Numerical Considerations in the Modeling of a High Explosive Cylinder Experiment Using an ALE Continuum Mechanics Code

A series of experiments involving the detonation of PBX 9501 encased in a copper cylinder are modeled with the objective of evaluating a proposed set of phenomenological parameters for the Wescott–Stewart–Davis reactive burn model. The numerical analysis is conducted using the Los Alamos continuum mechanics code FLAG. Numerical considerations pertaining to various aspects of modeling the experiments using FLAG are discussed. It is shown that use of the proposed set of phenomenological parameters results in predictions of free-surface velocity that match empirically measured velocities reasonably well.

Experimental approach to thermal conductivity of macro solder joints with voids

Purpose The purpose of the paper is to experimentally evaluate the impact of voids on thermal conductivity of a macro solder joint formed between a copper cylinder and a copper plate by using reflow soldering. Design/methodology/approach A model of a surface mount device (SMD) was developed in the shape of a cylinder. A copper plate works as a printed circuit board (PCB). The resistor was connected to a power supply and the plate was cooled by a heat sink and a powerful fan. A macro solder joint was formed between a copper cylinder and a copper plate using reflow soldering and a lead-free solder paste SAC305. The solder paste was printed on a plate through stencils of various apertures. It was expected that various apertures of stencils will moderate the various void contents in solder joints. K-type thermocouples mounted inside cylinders and at the bottom of a plate underneath the cylinders measured the temperature gradient on both sides of the solder joint. After finishing the temperature measurements, the cylinders were thinned by milling to thickness of about 2 mm and then X-ray images were taken to evaluate the void contents. Finally the tablets were cross-sectioned to enable scanning electron microscopy (SEM) observations. Findings There was no clear dependence between thermal conductivity of solder joints and void contents. The authors state that other factors such as intermetallic layers, microcracks, crystal grain morfologyof the interface between the solder and the substrate influence on thermal conductivity. To support this observation, further investigations using metallographic methods are required. Originality/value Results allow us to assume that the use of SAC305 alloy for soldering of components with high thermal loads is risky. The common method for thermal balance calculation is based on the sum of serial thermal resistances of mechanical compounds. For these calculations, solder joints are represented with bulk SAC305 thermal conductivity parameters. Thermal conductivity of solder joints for high density of thermal energy is much lower than expected. Solder joints’ structure is not fully comparable with bulk SAC305 alloy. In experiments, the average value of the solder joint conductivity was found to be 8.1 W/m·K, which is about 14 per cent of the nominal value of SAC305 thermal conductivity.

Smart Travel Mug for Hot and Cold Beverages

Disposable cups tend to be a viable solution as a packaging method for hot or cold beverages, but they have adverse environmental impact. They represent a concern for consumers due to the excessive use of trees during production of paper cups and non-biodegradability of plastic cups. The mobility and convenience of reheating the beverage in a microwave oven, for example, encourages the use of disposable cups. In this project, an environmentally-friendly solution is presented to reduce the use of plastic and paper cups that harm the environment. Compared to other existing products, this device maintains a desired temperature of a hot or cold beverage for extended periods of time using insulation and power from a thermoelectric cooler. The proposed design consists of a double-wall mug with outer steel and inner copper cylinders. The base of the copper cylinder is integrated with a thermoelectric cooler and a control system. The development of the device is governed by the performance of preserving desired temperature of beverages for longer times compared to conventional mugs and containers. Testing methods consist of thermal FEA simulation, CFD simulation and physical prototype testing showing a temperature difference of 30 °C with the added thermal system to the mug.

Death cults in Gothic ‘Lost World’ fiction

This chapter examines the ‘Lost World’ genre, a staple of late-Victorian popular fiction, exemplified by H. Rider Haggard’s stories featuring Allan Quatermain, and Ayesha, known as She-Who-Must-Be-Obeyed. These fin-de-siècle tales, while ostensibly celebrating British Imperialism and the continuation of colonial power, reveal layers of anxiety concerning degeneration, the collapse of civilisation, the rise of the Victorian ‘new woman’, and perhaps most potently the fear of death. Canadian writer James De Mille, in his book A Strange Manuscript Found in a Copper Cylinder, inverted Victorian values to satirise the capitalist economy, and the glorification of war, by creating the Lost World of the Kosekin where wealth is a burden and death worshipped. The presentation of the Lost World as a Gothic Space allows for a critical examination of the way that Victorian cultural certainties were challenged, by divergent belief systems, and the mystery and terror of death.

Effect of Annealing Process on the Performance of Pressure of the φ3.5mm×8.75mm Cylindrical Copper Cylinder

By using different annealing processes to anneal the pressure-measuring cylindrical copper cylinder, playing some static experiments on different copper cylinders, the difference of pressure measuring performance of copper cylinder was analyzed. Results show that, by using current annealing processes all can achieve the purpose of full softening the material of the copper cylinder and the deformation of copper is not significantly affected by the different temperatures. Some copper cylinders which use short holding time have poor linear sensitivity, but their measurement deviation is better than those which use longer holding time. So, in the actual production of copper, we should use shorter annealing time to improve their measuring accuracy.

Corrosion Inhibition of a Gas Sparged Copper Cylinder in a Solution of NaCl and Na2S by Using 4-Amino-4H-1,2,4-triazole as Corrosion Inhibitor

Most of previous investigations for corrosion inhibition of copper using triazole derivatives were carried out in stagnant conditions and mainly in presence either NaCl or Na2S. The main aim of this work is to investigate the performance of one of triazole derivatives namely, 4-Amino-4H-1,2,4-triazole (AHT) on improving the corrosion resistance of gas sparged copper parts in a solution comprised of NaCl and Na2S with different propotions. The potentiodynamic technique was used for investigating the effect of different variables on the corrosion rate of gas sparged copper such as gas velocity, initial S-2 concentration, gas sparged copper cylinder diameter, and initial AHT inhibitor concentration. The results show that the %improvement in corrosion resistance depends mainly on two main parameters, gas flow rate and amount of AHT inhibitor added. For lower gas velocities 0.07 cm/s the %improvement ranges from 6 to 22%, while for higher gas rate 0.35 cm/s it ranges from 2 to 7% depending on the amount of inhibitor added. The activation energy of the reaction was found to increase by approximately 20% by addition of the inhibitor up to 10ppm.